Multi-layer composite materials comprising a foam layer, corresponding method of production and use thereof

ABSTRACT

Multi-layer composite materials comprising a foam layer, corresponding method of production and use thereof. 
     Multilayered composite materials comprising as components:
     (A) a foam layer where the foam is selected from polystyrene foams, polyurethane foams, polyester foams, butadiene-styrene block copolymer foams, natural sponges and amino resin foams,   (B) optionally at least one bonding layer and   (C) a polyurethane layer.

The present invention relates to a multilayered composite materialcomprising as components:

-   (A) a foam layer where the foam is selected from polystyrene foams,    polyurethane foams, polyester foams, butadiene-styrene block    copolymer foams, natural sponges and amino resin foams,-   (B) optionally at least one bonding layer and-   (C) a polyurethane layer.

The present invention further relates to a process for producing themultilayered composite materials of the present invention and their use.

Foams are in demand for many applications. They have good properties asmaterials for thermal insulation and are also in demand as packagingmaterials. They can also be used as material for acoustical insulation.

However, it is disadvantageous in many cases that the appearance of thefoams in question is not attractive. In addition, such foams are oftendifficult to clean and therefore tend to become soiled easily.

Attempts are made in many cases to improve their wash-off-ability byadhering a self-supporting polyolefin, for example a polyethylene orpolypropylene, film to them. Yet this does not improve the appearance inall cases. Moreover, the “hand” i.e., the haptic properties, ofself-supporting polyolefin films is not always ideal.

The present invention has for its object to process foams such that theyhave a pleasant hand and an attractive appearance and that they are alsoefficiently cleanable. The present invention further has for its objectto provide a process for producing such foams.

We have found that this object is achieved by the multilayered compositematerials defined at the beginning. They comprise as components

-   (A) a foam layer where the foam is selected from polystyrene foams,    polyurethane foams, polyester foams, butadiene-styrene block    copolymer foams, natural sponges and amino resin foams,-   (B) optionally at least one bonding layer and-   (C) a polyurethane layer.

The foam layer (A), hereinafter also referred to in brief as foam (A) orfoam layer (A), may comprise various kinds of foams.

Foam is defined by German standard specification DIN 7726 as a materialof construction which has cells distributed throughout the entirematerial and an envelope density which is lower than the density of thescaffolding substance.

Foam (A) may be closed cell, but herein is preferably mostly open cell.In one embodiment of the present invention, 50% of all lamellae areopen, preferably 60 to 100% and more preferably 65 to 99.9%, determinedaccording to DIN ISO 4590. An open lamella (cell) is defined as a cellwhich communicates with other cells via the gas phase.

The density of foam (A) is preferably between 5 to 1000 kg/m³,preferably 6 to 300 kg/m³ and more preferably in the range from 7 to 250kg/m³.

In one embodiment of the present invention, foam (A) has a breakingextension of greater than 100%.

In one embodiment of the present invention, foam (A) can have a numberaverage pore diameter in the range from 1 μm to 1 mm and preferably inthe range from 50 to 500 μm, determined by evaluating micrographs ofsections.

In one specific embodiment of the present invention, foam (A) has a DIN52212 sound absorption of above 0.5, measured at a frequency of 2000 Hzand a layer thickness of 40 mm for the foam (A) in question.

Foam (A) may be of natural or synthetic origin. For example, foam (A)may be selected from natural sponges of the kind used as cleaningarticles for example.

Examples of synthetic foams are polystyrene foams, also known asexpanded polystyrene, polyurethane foams, butadiene-styrene blockcopolymer foams, polyester foams and amino resin foams.

Examples of amino resin foams are foams based on urea-formaldehyderesins, foams based on phenol-formaldehyde resins and in particularaminoplast-formaldehyde resins, in particular melamine-formaldehyderesins, the latter herein also being referred to as melamine foams.

Polyurethane foams may comprise rigid polyurethane foams, flexiblepolyurethane foams, so-called semirigid foams and viscoelasticpolyurethane foams.

The production of the aforementioned foams (A) and in particular ofmelamine foams is known per se, the latter and also polyurethane foamsbeing described at length in WO 2005/103107 for example.

In one embodiment of the present invention, foam layer (A) has athickness in the range from 100 μm to 10 cm; a thickness of 1 mm to 1 cmis preferred.

Foam (A) is not a coating on a textile.

Polyurethane layer (C) does not comprise a foam layer. Polyurethanelayer (C) is preferably produced from aqueous dispersion.

Polyurethane layer (C) may be present as an air-impermeable film. Theproduction of air-impermeable polyurethane films is known per se.

In an embodiment of the present invention, polyurethane layer (C) has anaverage thickness in the range from 15 to 300 μm, preferably in therange from 20 to 150 μm and more preferably in the range from 25 to 80μm.

In a preferred embodiment of the present invention, polyurethane layer(C) has capillaries which extend through the entire thickness (crosssection) of the polyurethane layer (C).

In an embodiment of the present invention, polyurethane layer (C) has onaverage at least 100 and preferably at least 250 capillaries per 100cm².

In an embodiment of the present invention, the capillaries have anaverage diameter in the range from 0.005 to 0.05 mm and preferably inthe range from 0.009 to 0.03 mm.

In an embodiment of the present invention, the capillaries are uniformlydistributed over polyurethane layer (C). In a preferred embodiment ofthe present invention, however, the capillaries are nonuniformlydistributed over the polyurethane layer (C).

In an embodiment of the present invention, the capillaries areessentially arcuate. In another embodiment of the present invention, thecapillaries have an essentially straight-line course.

The capillaries endow the polyurethane layer (C) with an air and watervapor permeability without any need for perforation. In an embodiment ofthe present invention, the water vapor permeability of the polyurethanelayer (C) can be above 1.5 mg/cm²·h, measured according to Germanstandard specification DIN 53333. It is thus possible for moisture suchas sweat for example to migrate through the polyurethane layer (C).

In an embodiment of the present invention, polyurethane layer (C) aswell as capillaries has pores which do not extend through the entirethickness of the polyurethane layer (C).

In one embodiment, polyurethane layer (C) exhibits patterning. Thepatterning is freely choosable and can reproduce for example thepatterning of a leather or of a wood surface. In an embodiment of thepresent invention, the patterning may reproduce a nubuck leather.

In an embodiment of the present invention, polyurethane layer (C) has avelvetlike appearance.

In an embodiment of the present invention, the patterning can correspondto a velvet surface, for example with small hairs having an averagelength in the range from 20 to 500 μm, preferably in the range from 30to 200 μm and more preferably in the range from 60 to 100 μm. The smallhairs can have for example a circle-shaped diameter. In a particularembodiment of the present invention, the small hairs have a cone-shapedform.

In an embodiment of the present invention, polyurethane layer (C) hassmall hairs with an average spacing of 50 to 350, preferably 100 to 250μm from one hair to the next.

When the polyurethane layer (C) has small hairs, the statements aboutthe average thickness apply to the polyurethane layer (C) without thesmall hairs.

The polyurethane layer (C) is bonded to foam (A) via at least onebonding layer (B).

Bonding layer (B) may comprise an interrupted, i.e., discontinuous,layer, preferably of a cured organic adhesive.

In an embodiment of the present invention, bonding layer (B) comprises alayer applied in point form, stripe form or lattice form, for example inthe form of diamonds, rectangles, squares or a honeycomb structure. Inthat case, polyurethane layer (C) comes into contact with foam (A) inthe gaps of the bonding layer (B).

In another embodiment of the present invention, bonding layer (B)comprises a continuous layer.

In an embodiment of the present invention, bonding layer (B) comprises alayer of a cured organic adhesive, for example based on polyvinylacetate, polyacrylate or in particular polyurethane, preferably based onpolyurethanes having a glass transition temperature below 0° C.

The organic adhesive may for example be cured thermally, through actinicradiation or by aging.

In another embodiment of the present invention, bonding layer (B)comprises an adhesive gauze.

In an embodiment of the present invention, the bonding layer (B) has amaximum thickness of 100 μm, preferably 50 μm, more preferably 30 μm,most preferably 15 μm.

In an embodiment of the present invention, bonding layer (B) maycomprise microballoons. Microballoons herein are spherical particleshaving an average diameter in the range from 5 to 20 μm and composed ofpolymeric material, in particular of halogenated polymer such as forexample polyvinyl chloride or polyvinylidene chloride or copolymer ofvinyl chloride with vinylidene chloride. Microballoons may be empty orpreferably filled with a substance whose boiling point is slightly lowerthan room temperature, for example with n-butane and in particular withisobutane.

In an embodiment of the present invention, polyurethane layer (C) may bebonded to foam (A) via at least two bonding layers (B) having the sameor a different composition. One bonding layer (B) may comprise a pigmentwith the other bonding layer (B) being pigment free.

In one variant, one bonding layer (B) may comprise microballoons withthe other bonding layer (B) not comprising microballoons.

In an embodiment of the present invention, multilayered compositematerial of the present invention can have no further layers. In anotherembodiment of the present invention, multilayered composite material ofthe present invention may comprise at least one interlayer (D) disposedbetween foam (A) and bonding layer (B), between bonding layer (B) andpolyurethane layer (C) or between two bonding layers (B), which may bethe same or different. Interlayer (D) is selected from textile, paper,batt materials, and batt materials (nonwovens) of synthetic materialssuch as polypropylene or polyurethane, in particular nonwovens ofthermoplastic polyurethane.

In those embodiments where multilayered composite material of thepresent invention comprises at least one interlayer (D), polyurethanelayer (C) will preferably come into direct contact not with foam (A),but with interlayer (D).

In an embodiment of the present invention, interlayer (D) may have anaverage diameter (thickness) in the range from 0.05 mm to 5 cm,preferably in the range from 0.1 mm to 0.5 cm and more preferably in therange from 0.2 mm to 2 mm.

Preferably, interlayer (D) has a water vapor permeability in the rangeof greater than 1.5 mg/cm²·h, measured according to German standardspecification DIN 53333.

Multilayered composite materials of the present invention have a highmechanical strength and fastnesses. They further have a high water vaporpermeability. Drops of spilt liquid are easy to remove, for example witha cloth. Multilayered composite materials of the present invention alsohave an attractive appearance and a very pleasant soft hand.

The use of multilayered composite material of the present invention isfor example advantageous in seats for means of transport such as boats,automobiles, airplanes, railroad vehicles, street cars, buses and, inparticular, in child seats. Multilayered composite material of thepresent invention can also be used with advantage elsewhere in theinteriors of vehicles, for example in roof liners, interior trim andcenter consoles. It is further advantageous to use multilayeredcomposite materials of the present invention for cleaning sponges,insulating materials, in particular in buildings, for example thermal oracoustical insulants, and also for seating furniture.

The present invention further provides a process for producingmultilayered composite materials of the present invention, herein alsoreferred to as inventive production process. An embodiment of theinventive production process proceeds by forming a polyurethane layer(C) with the aid of a mold, applying at least one organic adhesiveuniformly or partially onto foam (A) and/or onto polyurethane layer (C)and then bonding polyurethane layer (C) pointwise, stripwise or areawiseto foam (A).

In an embodiment of the present invention, multilayered compositematerial of the present invention is produced by a coating process byfirst providing a polyurethane film (C), coating at least foam (A) orthe polyurethane film (C) or both with organic adhesive on one face ineach case, partially, for example in the form of a pattern, and thenbringing the two faces into contact with each other. Thereafter, thesystem thus obtainable can additionally be pressed together or thermallytreated or pressed together while being heated.

The polyurethane film (C) forms the later polyurethane layer (C) of themultilayered composite material of the present invention. Thepolyurethane film (C) can be produced as follows:

An aqueous polyurethane dispersion is applied to a mold, which ispreheated, the water is allowed to evaporate and then the resultingpolyurethane film (C) is transferred to foam (A).

Aqueous polyurethane dispersion can be applied to the mold byconventional methods, in particular by spraying, for example with aspray gun.

The mold may exhibit patterning, also referred to as structuring, forexample produced by laser engraving or by molding with a negative mold.

An embodiment of the present invention comprises providing a mold havingan elastomeric layer or a layer composite, comprising an elastomericlayer on a support, the elastomeric layer comprising a binder and alsoif appropriate further, additive and auxiliary materials. Providing amold can then comprise the following steps:

-   1) applying a liquid binder, comprising additive and/or auxiliary    materials if appropriate, to a patterned surface, for example    another mold or an original pattern,-   2) curing the binder, for example by thermal curing, radiative    curing or by allowing to age,-   3) separating the mold thus obtainable and if appropriate applying    it to a support, for example a metal plate or a metal cylinder.

An embodiment of the present invention proceeds by a liquid siliconebeing applied to a pattern, the silicone being allowed to age and thuscure and then stripping. The silicone film is then adhered to analuminum support.

A preferred embodiment of the present invention provides a moldcomprising a laser-engravable layer or a layer composite comprising alaser-engravable layer on a support, the laser-engravable layercomprising a binder and also, if appropriate, further, additive andauxiliary materials. The laser-engravable layer is preferably alsoelastomeric.

In a preferred embodiment, the providing of a mold comprises the stepsof:

-   1) providing a laser-engravable layer or a layer composite    comprising a laser-engravable layer on a support, the    laser-engravable layer comprising a binder and also, preferably,    additive and auxiliary materials,-   2) thermochemical, photochemical or actinic amplification of the    laser-engravable layer,-   3) engraving into the laser-engravable layer, using a laser, a    surface structure corresponding to the surface structure of the    surface-structured coating.

The laser-engravable layer, which is preferably elastomeric, or thelayer composite can be and preferably are present on a support. Examplesof suitable supports comprise woven fabrics and self-supportingfilms/sheets of polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), polybutylene terephthalate (PBT), polyethylene,polypropylene, polyamide or polycarbonate, preferably PET or PENself-supporting films/sheets.

Useful supports likewise include papers and knits, for example ofcellulose. As supports there may also be used conical or cylindricalsleeves of the materials mentioned. Also suitable for sleeves are glassfiber fabrics or composite materials comprising glass fibers andpolymeric materials of construction. Suitable support materials furtherinclude metallic supports such as for example solid or fabric-shaped,sheetlike or cylindrical supports of aluminum, steel, magnetizablespring steel or other iron alloys.

In an embodiment of the present invention, the support may be coatedwith an adhesion-promoting layer to provide better adhesion of thelaser-engravable layer. Another embodiment of the present inventionrequires no adhesion-promoting layer.

The laser-engravable layer comprises at least one binder, which may be aprepolymer which reacts in the course of a thermochemical amplificationto form a polymer. Suitable binders can be selected according to theproperties desired for the laser-engravable layer or the mold, forexample with regard to hardness, elasticity or flexibility. Suitablebinders can essentially be divided into 3 groups, without there beingany intention to limit the binders thereto.

The first group comprises those binders which have ethylenicallyunsaturated groups. Ethylenically unsaturated groups are crosslinkablephotochemically, thermochemically, by means of electron beams or bymeans of any desired combination thereof. In addition, mechanicalamplification is possible by means of fillers. Such binders are forexample those comprising 1,3-diene monomers such as isoprene or1,3-butadiene in polymerized form. The ethylenically unsaturated groupmay either function as a chain building block of the polymer(1,4-incorporation), or it may be bonded to the polymer chain as a sidegroup (1,2-incorporation). As examples there may be mentioned naturalrubber, polybutadiene, polyisoprene, styrene-butadiene rubber,nitrile-butadiene rubber, acrylonitrile-butadiene-styrene (ABS)copolymer, butyl rubber, styrene-isoprene rubber, polychloroprene,polynorbornene rubber, ethylene-propylene-diene monomer (EPDM) rubber orpolyurethane elastomers having ethylenically unsaturated groups.

Further examples comprise thermoplastic elastomeric block copolymers ofalkenyl-aromatics and 1,3-dienes. The block copolymers may compriseeither linear block copolymers or else radical block copolymers.Typically they are three-block copolymers of the A-B-A type, but theymay also comprise two-block polymers of the A-B type, or those having aplurality of alternating elastomeric and thermoplastic blocks, forexample A-B-A-B-A. Mixtures of two or more different block copolymerscan also be used. Commercially available three-block copolymersfrequently comprise certain proportions of two-block copolymers. Dieneunits may be 1,2- or 1,4-linked. Block copolymers of thestyrene-butadiene type and also of the styrene-isoprene type can beused. They are commercially available under the name Kraton® forexample. It is also possible to use thermoplastic elastomeric blockcopolymers having end blocks of styrene and a random styrene-butadienemiddle block, which are available under the name Styroflex®.

Further examples of binders having ethylenically unsaturated groupscomprise modified binders in which crosslinkable groups are introducedinto the polymeric molecule through grafting reactions.

The second group comprises those binders which have functional groups.The functional groups are crosslinkable thermochemically, by means ofelectron beams, photochemically or by means of any desired combinationthereof. In addition, mechanical amplification is possible by means offillers. Examples of suitable functional groups comprise —Si(HR¹)O—,—Si(R¹R²)O—, —OH, —NH₂, —NHR¹, —COOH, —COOR¹, —COHN₂, —O—C(O)NHR¹, —SO₃Hor —CO—. Examples of binders comprise silicone elastomers, acrylaterubbers, ethylene-acrylate rubbers, ethylene-acrylic acid rubbers orethylene-vinyl acetate rubbers and also their partially hydrolyzedderivatives, thermoplastic elastomeric polyurethanes, sulfonatedpolyethylenes or thermoplastic elastomeric polyesters. In the formulae,R¹, and—if present —R² are different or preferably the same and are eachselected from organic groups and in particular C₁-C₆-alkyl.

An embodiment of the present invention comprises using binders havingboth ethylenically unsaturated groups and functional groups. Examplescomprise addition-crosslinking silicone elastomers having functionalgroups and ethylenically unsaturated groups, copolymers of butadienewith (meth)acrylates, (meth)acrylic acid or acrylonitrile, and alsocopolymers or block copolymers of butadiene or isoprene with styrenederivatives having functional groups, examples being block copolymers ofbutadiene and 4-hydroxystyrene.

The third group of binders comprises those which have neitherethylenically unsaturated groups nor functional groups. There may bementioned for example polyolefins or ethylene-propylene elastomers orproducts obtained by hydrogenation of diene units, for example SEBSrubbers.

Polymer layers comprising binders without ethylenically unsaturated orfunctional groups generally have to be amplified mechanically, with theaid of high-energy radiation or a combination thereof in order to permitoptimum crisp structurability via laser.

It is also possible to use mixtures of two or more binders, in whichcase the two or more binders in any one mixture may all just come fromone of the groups described or may come from two or all three groups.The possible combinations are only limited insofar as the suitability ofthe polymer layer for the laser-structuring operation and thenegative-molding operation must not be adversely affected. It may beadvantageous to use for example a mixture of at least one elastomericbinder having no functional groups with at least one further binderhaving functional groups or ethylenically unsaturated groups.

In an embodiment of the present invention, the proportion of binder orbinders in the elastomeric layer or the particular laser-engravablelayer is in the range from 30% by weight to 99% by weight based on thesum total of all the constituents of the particular elastomeric layer orthe particular laser-engravable layer, preferably in the range from 40%to 95% by weight and most preferably in the range from 50% to 90% byweight.

In an embodiment of the present invention, polyurethane layer (C) isformed with the aid of a silicone mold. Silicone molds herein are moldsprepared using at least one binder having at least one and preferably atleast three O—Si(R¹R²)—O— groups per molecule, where the variables areeach as defined above.

Optionally, the elastomeric layer or laser-engravable layer may comprisereactive low molecular weight or oligomeric compounds. Oligomericcompounds generally have a molecular weight of not more than 20 000g/mol. Reactive low molecular weight and oligomeric compounds arehereinbelow simply referred to as monomers.

Monomers may be added to increase the rate of photochemical orthermochemical crosslinking or of crosslinking via high-energyradiation, if desired. When binders from the first and second groups areused, the addition of monomers for acceleration is generally notabsolutely essential. In the case of binders from the third group, theaddition of monomers is generally advisable without being absolutelyessential in every case.

Irrespective of the issue of crosslinking rate, monomers can also beused for controlling crosslink density. Depending on the identity andamount of low molecular weight compounds added, wider or narrowernetworks are obtained. Known ethylenically unsaturated monomers can beused first of all. The monomers should be substantially compatible withthe binders and have at least one photochemically or thermochemicallyreactive group. They should not be volatile. Preferably, the boilingpoint of suitable monomers is at least 150° C. Of particular suitabilityare amides of acrylic acid or methacrylic acid with mono- orpolyfunctional alcohols, amines, aminoalcohols or hydroxy ethers andhydroxy esters, styrene or substituted styrenes, esters of fumaric ormaleic acid, or allyl compounds. Examples comprise n-butyl acrylate,2-ethylhexyl acrylate, lauryl acrylate, 1,4-butanediol di(meth)acrylate,1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanedioldiacrylate, trimethylolpropane trimethacrylate, trimethylolpropanetriacrylate, dipropylene glycol diacrylate, tripropylene glycoldiacrylate, dioctyl fumarate, N-dodecylmaleimide and triallylisocyanurate.

Monomers suitable for thermochemical amplification in particularcomprise reactive low molecular weight silicones such as for examplecyclic siloxanes, Si—H-functional siloxanes, siloxanes having alkoxy orester groups, sulfur-containing siloxanes and silanes, dialcohols suchas for example 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol,1,9-nonanediol, diamines such as for example 1,6-hexanediamine,1,8-octanediamine, aminoalcohols such as for example ethanolamine,diethanolamine, butylethanolamine, dicarboxylic acids such as forexample 1,6-hexanedicarboxylic acid, terephthalic acid, maleic acid orfumaric acid.

It is also possible to use monomers having both ethylenicallyunsaturated groups and functional groups. As examples there may bementioned ω-hydroxyalkyl (meth)acrylates, such as for example ethyleneglycol mono(meth)acrylate, 1,4-butanediol mono(meth)acrylate or1,6-hexanediol mono(meth)acrylate.

It is of course also possible to use mixtures of different monomers,provided that the properties of the elastomeric layer are not adverselyaffected by the mixture. In general, the amount of added monomers is inthe range from 0% to 40% by weight, based on the amount of all theconstituents of the elastomeric layer or of the particularlaser-engravable layer, preferably in the range from 1% to 20% byweight.

In one embodiment, one or more monomers may be used together with one ormore catalysts. It is thus possible to accelerate silicone molds byaddition of one or more acids or via organotin compounds to acceleratestep 2) of the providing of the mold. Suitable organotin compounds canbe: di-n-butyltin dilaurate, di-n-butyltin dioctanoate, di-n-butyltindi-2-ethylhexanoate, di-n-octyltin di-2-ethylhexanoate anddi-n-butylbis-(1-oxoneodecyloxy)stannane.

The elastomeric layer or the laser-engravable layer may further compriseadditive and auxiliary materials such as for example IR absorbers, dyes,dispersants, antistats, plasticizers or abrasive particles. The amountof such additive and auxiliary materials should generally not exceed 30%by weight, based on the amount of all the components of the elastomericlayer or of the particular laser-engravable layer.

The elastomeric layer or the laser-engravable layer may be constructedfrom a plurality of individual layers. These individual layers may be ofthe same material composition, of substantially the same materialcomposition or of differing material composition. The thickness of thelaser-engravable layer or of all individual layers together is generallybetween 0.1 and 10 mm and preferably in the range from 0.5 to 3 mm. Thethickness can be suitably chosen depending on use-related andmachine-related processing parameters of the laser-engraving operationand of the negative molding operation.

The elastomeric layer or the laser-engravable layer may optionallyfurther comprise a top layer having a thickness of not more than 300 μm.The composition of such a top layer is chooseable with regard to optimumengravability and mechanical stability, while the composition of thelayer underneath is chosen with regard to optimum hardness orelasticity.

In an embodiment of the present invention, the top layer itself islaser-engravable or removable in the course of the laser-engravingoperation together with the layer underneath. The top layer comprises atleast one binder. It may further comprise an absorber for laserradiation or else monomers or auxiliaries.

In an embodiment of the present invention, the silicone mold comprises asilicone mold structured with the aid of laser engraving.

It is very particularly advantageous for the process according to thepresent invention to utilize thermoplastic elastomeric binders orsilicone elastomers. When thermoplastic elastomeric binders are used,production is preferably effected by extrusion between a supportfilm/sheet and a cover film/sheet or a cover element followed bycalendering, as disclosed in EP-A 0 084 851 for flexographic printingelements for example. Even comparatively thick layers can be produced ina single operation in this way. Multilayered elements can be produced bycoextrusion.

To structure the mold with the aid of laser engraving, it is preferableto amplify the laser-engravable layer before the laser-engravingoperation by heating (thermochemically), by exposure to UV light(photochemically) or by exposure to high-energy radiation (actinically)or any desired combination thereof.

Thereafter, the laser-engravable layer or the layer composite is appliedto a cylindrical (temporary) support, for example of plastic, glassfiber-reinforced plastic, metal or foam, for example by means ofadhesive tape, reduced pressure, clamping devices or magnetic force, andengraved as described above. Alternatively, the planar layer or thelayer composite can also be engraved as described above. Optionally, thelaser-engravable layer is washed using a rotary cylindrical washer or acontinuous washer with a cleaning agent for removing engraving residuesduring the laser-engraving operation.

The mold can be produced in the manner described as a negative mold oras a positive mold.

In a first variant, the mold has a negative structure, so that thecoating which is bondable to foam (A) is obtainable directly byapplication of a liquid plastics material to the surface of the mold andsubsequent solidification of the polyurethane.

In a second variant, the mold has a positive structure, so thatinitially a negative mold is produced from the laser-structured positivemold. The coating bondable to a sheetlike support can then be obtainedfrom this negative mold by application of a liquid plastics material tothe surface of the negative mold and subsequent solidification of theplastics material.

Preferably, structure elements having dimensions in the range from 10 to500 μm are engraved into the mold. The structure elements may be in theform of elevations or depressions. Preferably, the structure elementshave a simple geometric shape and are for example circles, ellipses,squares, rhombuses, triangles and stars. The structure elements may forma regular or irregular screen. Examples are a classic dot screen or astochastic screen, for example a frequency-modulated screen.

In an embodiment of the present invention, the mold is structured usinga laser to cut wells into the mold which have an average depth in therange from 50 to 250 μm and a center-to-center spacing in the range from50 to 250 μm.

For example, the mold can be engraved such that it has wells having adiameter in the range from 10 to 500 μm at the surface of the mold. Thediameter at the surface of the mold is preferably in the range from 20to 250 μm and more preferably 30-150 μm. The spacing of the wells can befor example in the range from 10 to 500 μm, preferably in the range from20 to 200 μm and more preferably up to 80 μm.

In an embodiment of the present invention, the mold preferably has asurface fine structure as well as a surface coarse structure. Bothcoarse structure and fine structure can be produced by laser engraving.The fine structure can be for example a microroughness having aroughness amplitude in the range from 1 to 30 μm and a roughnessfrequency in the range from 0.5 to 30 μm. The dimensions of themicroroughness are preferably in the range from 1 to 20 μm, morepreferably in the range from 2 to 15 μm and more preferably in the rangefrom 3 to 10 μm.

IR lasers in particular are suitable for laser engraving. However, it isalso possible to use lasers having shorter wavelengths, provided thelaser is of sufficient intensity. For example, a frequency-doubled (532nm) or frequency-tripled (355 nm) Nd-YAG laser can be used, or else anexcimer laser (248 nm for example). The laser-engraving operation mayutilize for example a CO₂ laser having a wavelength of 10 640 nm. It isparticularly preferable to use lasers having a wavelength in the rangefrom 600 to 2000 nm. Nd-YAG lasers (1064 nm), IR diode lasers orsolid-state lasers can be used for example. Nd/YAG lasers areparticularly preferred. The image information to be engraved istransferred directly from the lay-out computer system to the laserapparatus. The lasers can be operated either continuously or in a pulsedmode.

The mold obtained can generally be used directly as produced. Ifdesired, the mold obtained can additionally be cleaned. Such a cleaningstep removes loosened but possibly still not completely detached layerconstituents from the surface. In general, simply treating with water,water/surfactant, alcohols or inert organic cleaning agents which arepreferably low-swelling will be sufficient.

In a further step, an aqueous formulation of polyurethane is applied tothe mold. The applying may preferably be effected by spraying. The moldshould have been heated when the formulation of polyurethane is applied,for example to temperatures of at least 80° C., preferably at least 90°C. The water from the aqueous formulation of polyurethane evaporates andforms the capillaries in the solidifying polyurethane layer.

Aqueous in connection with the polyurethane dispersion is to beunderstood as meaning that the polyurethane dispersion comprises water,but less than 5% by weight, based on the dispersion, preferably lessthan 1% by weight of organic solvent. It is particularly preferable forthere to be no detectable volatile organic solvent. Volatile organicsolvents herein are such organic solvents as have a boiling point of upto 200° C. at standard pressure.

The aqueous polyurethane dispersion can have a solids content in therange from 5% to 60% by weight, preferably in the range from 10% to 50%by weight and more preferably in the range from 25% to 45% by weight.

Polyurethanes (PU) are common general knowledge, commercially availableand consist in general of a soft phase of comparatively high molecularweight polyhydroxy compounds, for example of polycarbonate, polyester orpolyether segments, and a urethane hard phase formed from low molecularweight chain extenders and di- or polyisocyanates.

Processes for preparing polyurethanes (PU) are common general knowledge.In general, polyurethanes (PU) are prepared by reaction of

-   (a) isocyanates, preferably diisocyanates, with-   (b) isocyanate-reactive compounds, typically having a molecular    weight (M_(w)) in the range from 500 to 10 000 g/mol, preferably in    the range from 500 to 5000 g/mol and more preferably in the range    from 800 to 3000 g/mol, and-   (c) chain extenders having a molecular weight in the range from 50    to 499 g/mol if appropriate in the presence of-   (d) catalysts-   (e) and/or customary additive materials.

In what follows, the starting components and processes for preparing thepreferred polyurethanes (PU) will be described by way of example. Thecomponents (a), (b), (c) and also if appropriate (d) and/or (e)customarily used in the preparation of polyurethanes (PU) will now bedescribed by way of example:

As isocyanates (a) there may be used commonly known aliphatic,cycloaliphatic, araliphatic and/or aromatic isocyanates, examples beingtri-, tetra-, penta-, hexa-, hepta- and/or octamethylene diisocyanate,2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene1,4-diisocyanate, pentamethylene 1,5-diisocyanate, butylene1,4-diisocyanate,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate, IPDI), 1,4- and/or 1,3-bis(isocyanatomethyl)cyclohexane(HXDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4- and/or-2,6-cyclohexane diisocyanate and/or 4,4′-, 2,4′- and2,2′-dicyclohexylmethane diisocyanate, 2,2′-, 2,4′- and/or4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate(NDI), 2,4- and/or 2,6-tolylene diisocyanate (TDI), diphenylmethanediisocyanate, 3,3′-dimethylbiphenyl diisocyanate, 1,2-diphenylethanediisocyanate and/or phenylene diisocyanate. Preference is given to using4,4′-MDI. Preference is also given to aliphatic diisocyanates, inparticular hexamethylene diisocyanate (HDI), and particular preferenceis given to aromatic diisocyanates such as 2,2′-, 2,4′- and/or4,4′-diphenyl-methane diisocyanate (MDI) and mixtures of theaforementioned isomers.

As isocyanate-reactive compounds (b) there may be used the commonlyknown isocyanate-reactive compounds, examples being polyesterols,polyetherols and/or polycarbonate diols, which are customarily alsosubsumed under the term “polyols”, having molecular weights (M_(w)) inthe range of 500 and 8000 g/mol, preferably in the range from 600 to6000 g/mol, in particular in the range from 800 to 3000 g/mol, andpreferably an average functionality of 1.8 to 2.3, preferably 1.9 to2.2, in particular 2, with regard to isocyanates. Preference is given tousing polyether polyols, for example those based on commonly knownstarter substances and customary alkylene oxides, for example ethyleneoxide, 1,2-propylene oxide and/or 1,2-butylene oxide, preferablypolyetherols based on polyoxytetramethylene (poly-THF), 1,2-propyleneoxide and ethylene oxide. Polyetherols have the advantage of having ahigher hydrolysis stability than polyesterols, and are preferably usedas component (b), in particular for preparing soft polyurethanespolyurethane (PU1).

As polycarbonate diols there may be mentioned in particular aliphaticpolycarbonate diols, for example 1,4-butanediol polycarbonate and1,6-hexanediol polycarbonate.

As polyester diols there are to be mentioned those obtainable bypolycondensation of at least one primary diol, preferably at least oneprimary aliphatic diol, for example ethylene glycol, 1,4-butanediol,1,6-hexanediol, neopentyl glycol or more preferably1,4-dihydroxymethylcyclohexane (as isomer mixture) or mixtures of atleast two of the aforementioned diols, and at least one, preferably atleast two dicarboxylic acids or their anhydrides. Preferred dicarboxylicacids are aliphatic dicarboxylic acids such as adipic acid, glutaricacid, succinic acid and aromatic dicarboxylic acids such as for examplephthalic acid and particularly isophthalic acid.

Polyetherols are preferably prepared by addition of alkylene oxides, inparticular ethylene oxide, propylene oxide and mixtures thereof, ontodiols such as for example ethylene glycol, 1,2-propylene glycol,1,2-butylene glycol, 1,4-butanediol, 1,3-propanediol, or onto triolssuch as for example glycerol, in the presence of high-activitycatalysts. Such high-activity catalysts are for example cesium hydroxideand dimetal cyanide catalysts, also known as DMC catalysts. Zinchexacyanocobaltate is a frequently employed DMC catalyst. The DMCcatalyst can be left in the polyetherol after the reaction, butpreferably it is removed, for example by sedimentation or filtration.

Mixtures of various polyols can be used instead of just one polyol.

To improve dispersibility, isocyanate-reactive compounds (b) may alsoinclude a proportion of one or more diols or diamines having acarboxylic acid group or sulfonic acid group (b′), in particular alkalimetal or ammonium salts of 1,1-dimethylolbutanoic acid,1,1-dimethylolpropionic acid or

Useful chain extenders (c) include commonly known aliphatic,araliphatic, aromatic and/or cycloaliphatic compounds having a molecularweight in the range from 50 to 499 g/mol and at least two functionalgroups, preferably compounds having exactly two functional groups permolecule, examples being diamines and/or alkanediols having 2 to 10carbon atoms in the alkylene radical, in particular 1,3-propanediol,1,4-butanediol, 1,6-hexanediol and/or di-, tri-, tetra-, penta-, hexa-,hepta-, octa-, nona- and/or decaalkylene glycols having 3 to 8 carbonatoms per molecule, preferably the corresponding oligo- and/orpolypropylene glycols, and mixtures of chain extenders (c) can also beused.

It is particularly preferable for components (a) to (c) to comprisedifunctional compounds, i.e., diisocyanates (a), difunctional polyols,preferably polyetherols (b) and difunctional chain extenders, preferablydiols.

Useful catalysts (d) to speed in particular the reaction between the NCOgroups of the diisocyanates (a) and the hydroxyl groups of the buildingblock components (b) and (c) are customary tertiary amines, for exampletriethylamine, dimethylcyclohexylamine, N-methylmorpholine,N,N′-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol,diazabicyclo-(2,2,2)octane (DABCO) and similar tertiary amines, and alsoin particular organic metal compounds such as titanic esters, ironcompounds such as for example iron(III) acetylacetonate, tin compounds,for example tin diacetate, tin dioctoate, tin dilaurate or the tindialkyl salts of aliphatic carboxylic acids such as dibutyltindiacetate, dibutyltin dilaurate or the like. The catalysts are typicallyused in amounts of 0.0001 to 0.1 part by weight per 100 parts by weightof component (b).

As well as catalyst (d), auxiliaries and/or additives (e) can also beadded to the components (a) to (c). There may be mentioned for exampleblowing agents, antiblocking agents, surface-active substances, fillers,for example fillers based on nanoparticles, in particular fillers basedon CaCO₃, nucleators, glidants, dyes and pigments, antioxidants, forexample against hydrolysis, light, heat or discoloration, inorganicand/or organic fillers, reinforcing agents and plasticizers, metaldeactivators. In a preferred embodiment, component (e) also includeshydrolysis stabilizers such as for example polymeric and low molecularcarbodiimides. The soft polyurethane preferably comprises triazoleand/or triazole derivative and antioxidants in an amount of 0.1% to 5%by weight based on the total weight of the soft polyurethane inquestion. Useful antioxidants are generally substances that inhibit orprevent unwanted oxidative processes in the plastics material to beprotected. In general, antioxidants are commercially available. Examplesof antioxidants are sterically hindered phenols, aromatic amines,thiosynergists, organophosphorus compounds of trivalent phosphorus andhindered amine light stabilizers. Examples of sterically hinderedphenols are to be found in Plastics Additive Handbook, 5th edition, H.Zweifel, Hanser Publishers, Munich, 2001 ([1]), pages 98-107 and page116-page 121. Examples of aromatic amines are to be found in [1] pages107-108. Examples of thiosynergists are given in [1], pages 104-105 andpages 112-113. Examples of phosphites are to be found in [1], pages109-112. Examples of hindered amine light stabilizers are given in [1]pages 123-136. Phenolic antioxidants are preferred for use in theantioxidant mixture. In a preferred embodiment, the antioxidants, inparticular the phenolic antioxidants, have a molar mass of greater than350 g/mol, more preferably greater than 700 g/mol and a maximum molarmass (M_(W)) of not more than 10 000 g/mol, preferably up to not morethan 3000 g/mol. They further preferably have a melting point of notmore than 180° C. It is further preferable to use antioxidants that areamorphous or liquid. Mixtures of two or more antioxidants can likewisebe used as component (e).

As well as the specified components (a), (b) and (c) and if appropriate(d) and (e), chain regulators (chain-terminating agents), customarilyhaving a molecular weight of 31 to 3000 g/mol, can also be used. Suchchain regulators are compounds which have only one isocyanate-reactivefunctional group, examples being monofunctional alcohols, monofunctionalamines and/or monofunctional polyols. Such chain regulators make itpossible to adjust flow behavior, in particular in the case of softpolyurethanes, to specific values. Chain regulators can generally beused in an amount of 0 to 5 parts and preferably 0.1 to 1 part byweight, based on 100 parts by weight of component (b), and by definitioncome within component (c).

As well as the specified components (a), (b) and (c) and if appropriate(d) and (e), it is also possible to use crosslinkers having two or moreisocyanate-reactive groups toward the end of the polyurethane-formingreaction, for example hydrazine hydrate.

To adjust the hardness of polyurethane (PU), the components (b) and (c)can be chosen within relatively wide molar ratios. Useful are molarratios of component (b) to total chain extenders (c) in the range from10:1 to 1:10, and in particular in the range from 1:1 to 1:4, thehardness of the soft polyurethanes increasing with increasing (c)content. The reaction to produce polyurethane (PU) can be carried out atan index in the range from 0.8 to 1.4:1, preferably at an index in therange from 0.9 to 1.2:1 and more preferably at an index in the rangefrom 1.05 to 1.2:1. The index is defined by the ratio of all theisocyanate groups of component (a) used in the reaction to theisocyanate-reactive groups, i.e., the active hydrogens, of components(b) and if appropriate (c) and if appropriate monofunctionalisocyanate-reactive components as chain-terminating agents such asmonoalcohols for example.

Polyurethane (PU) can be prepared by conventional processes in acontinuous manner, for example by the one-shot or the prepolymerprocess, or batchwise by the conventional prepolymer operation. In theseprocesses, the reactant components (a), (b), (c) and if appropriate (d)and/or (e) can be mixed in succession or simultaneously, and thereaction ensues immediately.

Polyurethane (PU) can be dispersed in water in a conventional manner,for example by dissolving polyurethane (PU) in acetone or preparing itas a solution in acetone, admixing the solution with water and thenremoving the acetone, for example distillatively. In one variant,polyurethane (PU) is prepared as a solution in N-methylpyrrolidone orN-ethylpyrrolidone, admixed with water and the N-methylpyrrolidone orN-ethylpyrrolidone is removed.

In an embodiment of the present invention, aqueous dispersions of thepresent invention comprise two different polyurethanes polyurethane(PU1) and polyurethane (PU2), of which polyurethane (PU1) is a so-calledsoft polyurethane which is constructed as described above forpolyurethane (PU), and at least one hard polyurethane (PU2).

Hard polyurethane (PU2) can in principle be prepared similarly to softpolyurethane (PU1), but other isocyanate-reactive compounds (b) or othermixtures of isocyanate-reactive compounds (b), herein also referred toas isocyanate-reactive compounds (b2) or in short compound (b2), areused.

Examples of compounds (b2) are in particular 1,4-butanediol,1,6-hexanediol and neopentyl glycol, either mixed with each other ormixed with polyethylene glycol.

In one version of the present invention, diisocyanate (a) andpolyurethane (PU2) are each mixtures of diisocyanates, for examplemixtures of HDI and IPDI, larger proportions of IPDI being chosen forthe preparation of hard polyurethane (PU2) than for the preparation ofsoft polyurethane (PU1).

In an embodiment of the present invention, polyurethane (PU2) has aShore A hardness in the range from above 60 to not more than 100, theShore A hardness being determined in accordance with German standardspecification DIN 53505 after 3 s.

In an embodiment of the present invention, polyurethane (PU) has anaverage particle diameter in the range from 100 to 300 nm and preferablyin the range from 120 to 150 nm, determined by laser light scattering.

In an embodiment of the present invention, soft polyurethane (PU1) hasan average particle diameter in the range from 100 to 300 nm andpreferably in the range from 120 to 150 nm, determined by laser lightscattering.

In an embodiment of the present invention, polyurethane (PU2) has anaverage particle diameter in the range from 100 to 300 nm and preferablyin the range from 120 to 150 nm, determined by laser light scattering.

The aqueous polyurethane dispersion may further comprise at least onecurative, which may also be referred to as a crosslinker. Compounds areuseful as a curative which are capable of crosslinking a plurality ofpolyurethane molecules together, for example on thermal activation. Ofparticular suitability are crosslinkers based on trimeric diisocyanates,in particular based on aliphatic diisocyanates such as hexamethylenediisocyanate. Very particular preference is given to crosslinkers offormula I a or I b, herein also referred to in brief as compound (V)

where R³, R⁴ and R⁵ may be different or preferably the same and are eachselected from A¹-NCO and A¹-NH—CO—X, where

A¹ is a spacer having 2 to 20 carbon atoms, selected from arylene,unsubstituted or substituted with one to four C₁-C₄-alkyl groups,alkylene and cycloalkylene, for example 1,4-cyclohexylene. Preferredspacers A¹ are phenylene, in particular para-phenylene, also tolylene,in particular para-tolylene, and C₂-C₁₂-alkylene such as for exampleethylene (CH₂CH₂), also —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅—, —(CH₂)₆—,—(CH₂)₈—, —(CH₂)₁₀—, —(CH₂)₁₂—.

X is selected from O(AO)_(x)R⁶, where

AO is C₂-C₄-alkylene oxide, for example butylene oxide, in particularethylene oxide (CH₂CH₂O) and propylene oxide (CH(CH₃)CH₂O) or(CH₂CH(CH₃)O),

x is an integer from 1 to 50, preferably 5 to 25, and

R⁶ is selected from hydrogen and C₁-C₃₀-alkyl, in particularC₁-C₁₀-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl,neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, more preferablyC₁-C₄-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl and tert-butyl.

Particularly preferred compounds (V) are those wherein R³, R⁴ and R⁵ areeach the same (CH₂)₄—NCO, (CH₂)₆—NCO or (CH₂)₁₂—NCO.

Aqueous polyurethane dispersions may comprise further constituents, forexample (f) a silicone compound having reactive groups,

herein also referred to as silicone compound (f).

Examples of reactive groups in connection with silicone compounds (f)are for example carboxylic acid groups, carboxylic acid derivatives suchas for example methyl carboxylate or carboxylic anhydrides, inparticular succinic anhydride groups, and more preferably carboxylicacid groups.

Examples of reactive groups further include primary and secondary aminogroups, for example NH(iso-C₃H₇) groups, NH(n-C₃H₇) groups,NH(cyclo-C₆H₁₁) groups and NH(n-C₄H₉) groups, in particular NH(C₂H₅)groups and NH(CH₃) groups, and most preferably NH₂ groups.

Preference is further given to aminoalkylamino groups such as forexample —NH—CH₂—CH₂—NH₂ groups, —NH—CH₂—CH₂—CH₂—NH₂ groups,—NH—CH₂—CH₂—NH(C₂H₅) groups, —NH—CH₂—CH₂—CH₂—NH(C₂H₅) groups,—NH—CH₂—CH₂—NH(CH₃) groups, —NH—CH₂—CH₂—CH₂—NH(CH₃) groups.

The reactive group or groups are attached to silicone compound (f)either directly or preferably via a spacer A². A² is selected fromarylene, unsubstituted or substituted with one to four C₁-C₄-alkylgroups, alkylene and cycloalkylene such as for example1,4-cyclohexylene. Preferred spacers A² are phenylene, in particularpara-phenylene, also tolylene, in particular para-tolylene, andC₂-C₁₈-alkylene such as for example ethylene (CH₂CH₂), also —(CH₂)₃—,—(CH₂)₄—, —(CH₂)₅—, —(CH₂)₆—, —(CH₂)₈—, —(CH₂)₁₆—, —(CH₂)₁₂—, —(CH₂)₁₄—,—(CH₂)₁₆— and —(CH₂)₁₈—.

In addition to the reactive groups, silicone compound (f) comprisesnon-reactive groups, in particular di-C₁-C₁₀-alkyl-SiO₂ groups orphenyl-C₁-C₁₀-alkyl-SiO₂ groups, in particular dimethyl-SiO₂ groups, andif appropriate one or more Si(CH₃)₂—OH groups or Si(CH₃)₃ groups.

In an embodiment of the present invention, silicone compound (f) has onaverage one to four reactive groups per molecule.

In an advantageous embodiment of the present invention, siliconecompound (f) has on average one to four COOH groups per molecule.

In another advantageous embodiment of the present invention, siliconecompound (f) has on average one to four amino groups or aminoalkylaminogroups per molecule.

Silicone compound (f) comprises Si—O—Si units in a chain-shaped orbranched arrangement.

In an embodiment of the present invention, silicone compound (f) has amolecular weight M_(n) in the range from 500 to 10 000 g/mol, preferablyup to 5000 g/mol.

When silicone compound (f) has two or more reactive groups per molecule,these reactive groups can be attached—directly or via spacer A²- to theSi—O—Si chain via two or more silicon atoms or pairwise via the samesilicon atom.

The reactive group or groups may be attached to one or more of theterminal silicon atoms of silicone compound (f)—directly or via spacerA². In another embodiment of the present invention, the reactive groupor groups are attached to one or more of the non-terminal silicon atomsof silicone compound (f)—directly or via spacer A².

In an embodiment of the present invention, aqueous polyurethanedispersion further comprises

a polydi-C₁-C₄-alkylsiloxane (g) having neither amino groups nor COOHgroups, preferably a polydimethylsiloxane, herein also referred to inbrief as polydialkylsiloxane (g) or polydimethylsiloxane (g).

The C₁-C₄-alkyl in polydialkylsiloxane (g) may be different orpreferably the same and selected from methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, of whichunbranched C₁-C₄-alkyl is preferred and methyl is particularlypreferred.

Polydialkylsiloxane (g) and preferably polydimethylsiloxane (g)preferably comprises unbranched polysiloxanes having Si—O—Si chains orsuch polysiloxanes as have up to 3 and preferably not more than onebranching per molecule.

Polydialkylsiloxane (D) and in particular polydimethylsiloxane (g) mayhave one or more Si(C₁-C₄-alkyl)₂-OH groups.

In an embodiment of the present invention, aqueous polyurethanedispersion comprises

altogether from 20% to 30% by weight of polyurethane (PU), or altogetherfrom 20% to 30% by weight of polyurethanes (PU1) and (PU2),

if appropriate from 1% to 10%, preferably 2% to 5% by weight ofcurative,

if appropriate from 1% to 10% by weight of silicone compound (f),

from zero to 10%, preferably 0.5% to 5% by weight of polydialkylsiloxane(g).

In an embodiment of the present invention, aqueous polyurethanedispersion comprises

from 10% to 30% by weight of soft polyurethane (PU1) and

from zero to 20% by weight of hard polyurethane (PU2).

In an embodiment of the present invention, aqueous polyurethanedispersion has a solids content of altogether 5% to 60% by weight,preferably 10% to 50% by weight and more preferably 25% to 45% byweight.

These weight % ages each apply to the active or solid ingredient and arebased on the total aqueous polyurethane dispersion. The remainder ad100% by weight is preferably continuous phase, for example water or amixture of one or more organic solvents and water.

In an embodiment of the present invention, aqueous polyurethanedispersion comprises at least one additive (h) selected from pigments,antilusterants, light stabilizers, antistats, antisoil, anticreak,thickening agents, in particular thickening agents based onpolyurethanes, and microballoons.

In an embodiment of the present invention, aqueous polyurethanedispersion comprises all together up to 20% by weight of additives (h).

Aqueous polyurethane dispersion may also comprise one or more organicsolvents. Suitable organic solvents are for example alcohols such asethanol or isopropanol and in particular glycols, diglycols, triglycolsor tetraglycols and doubly or preferably singly C₁-C₄-alkyl etherifiedglycols, diglycols, triglycols or tetraglycols. Examples of suitableorganic solvents are ethylene glycol, propylene glycol, butylene glycol,diethylene glycol, triethylene glycol, tetraethylene glycol, dipropyleneglycol, 1,2-dimethoxyethane, methyltriethylene glycol(“methyltriglycol”) and triethylene glycol n-butyl ether(“butyltriglycol”).

Aqueous polyurethane dispersions can be produced by mixing polyurethane(PU), curative and silicone compound (f) with water and if appropriateone or more of the aforementioned organic solvents. If desired,polydialkylsiloxane (g) and additives (h) are also mixed in. The mixingcan take the form of stirring for example. The order of addition ofpolyurethane (PU), curative, silicone compound (f) and water and ifappropriate one or more of the aforementioned organic solvents andalso—if desired—polydialkylsiloxane (g) and additives (h) is freelychoosable.

It is preferable to proceed from a polyurethane (PU) dispersed in wateror a mixture of water and organic solvent or from dispersed softpolyurethane (PU1) and hard polyurethane (PU2) and adding, preferablywith stirring, curative and silicone compound (f) and also, if desired,polydialkylsiloxane (g) and if appropriate one or more organic solvents.Preferably, however, no organic solvent is added.

In an advantageous embodiment, thickening agent as an example ofadditive (h) is added last to thus adjust the viscosity of the aqueouspolyurethane dispersion to the desired value.

After polyurethane layer (C) has cured, it is separated from the mold,for example by peeling off, to obtain a polyurethane film (C) whichforms the polyurethane layer (C) in multilayered composite material ofthe present invention.

In a further operation of the inventive production process, preferablyorganic adhesive is applied to polyurethane film (C) or to foam (A)non-uniformly, for example in the form of points, dots or stripes. Inone version of the present invention, one preferably organic adhesive isapplied to the polyurethane film (C) and one preferably organic adhesiveis applied to foam (A), the two adhesives differing, for example byvirtue of one or more additives or because they comprise chemicallydifferent preferably organic adhesives. Thereafter, polyurethane film(C) and foam (A) are bonded together, such that the layer(s) of adhesivecome to reside between the polyurethane film (C) and foam (A). Theadhesive or adhesives are cured, for example thermally, by means ofactinic radiation or by aging, to obtain multilayered composite materialof the present invention.

In an embodiment of the present invention, an interlayer (D) is placedbetween foam (A) and bonding layer (B), between bonding layer (B) andpolyurethane layer (C) or between two bonding layers (B).

The interlayer (D) is as defined above.

The placing can be done manually or mechanically, continuously orbatchwise.

The present invention further provides for the use of multilayeredcomposite materials of the present invention for producing seats. Seatsare for example seats for means of transport such as boats, automobiles,airplanes, railroad vehicles, street cars, buses and, in particular,child seats. The present invention further provides a process forproducing seats by using multilayered composite materials of the presentinvention. The present invention further provides seats comprising amultilayered composite material of the present invention. Only littleperspiration collects on surfaces of seats according to the presentinvention; moisture and also other liquids/fluids are absorbed.

The present invention further provides for the use of multilayeredcomposite materials of the present invention in the interiors ofvehicles, for example in arm rests, roof liners, interior trim andcenter consoles. Multilayer composite materials of the present inventionhave not only visual appeal, but also a very pleasant hand, and can havea thermally and/or acoustically insulating effect. The present inventionfurther provides vehicles containing at least one multilayered compositematerial of the present invention in an interior.

A further use of multilayered composite materials of the presentinvention is in electrical appliances and their packaging, for examplecell phones and covers for cell phones, games consoles, keyboards forcomputers. A further use for multilayered composite materials of thepresent invention is in the production of furniture, for example sofas,furniture for lying on such as loungers, armchairs and chairs. A furtheruse for composite materials of the present invention is as or for theproduction of elements for the interiors of buildings, for example forinsulation against heat loss and sound.

The present invention further provides for the use of compositematerials of the present invention as or for the production of cleaningsponges. Cleaning sponges of the present invention have an attractiveexterior.

Working examples further elucidate the present invention.

I. Production of Starting Materials

I.1 Production of an Aqueous Polyurethane Dispersion Disp.1

The following were mixed in a stirred vessel:

7% by weight of an aqueous dispersion (particle diameter: 125 nm, solidscontent: 40%) of a soft polyurethane (PU1.1) prepared from hexamethylenediisocyanate (a1.1) and isophorone diisocyanate (a1.2) in a weight ratioof 13:10 as diisocyanates and as diols, a polyester diol (b1.1) having amolecular weight M_(w) of 800 g/mol, prepared by polycondensation ofisophthalic acid, adipic acid and 1,4-dihydroxymethylcyclohexane (isomermixture) in a molar ratio of 1:1:2, 5% by weight of 1,4-butanediol(b1.2) and also 3% by weight of monomethylated polyethylene glycol (c.1)and also 3% by weight of H₂N—CH₂CH₂—NH—CH₂CH₂—COOH, % by weight allbased on polyester diol (b1.1), softening point of soft polyurethane(PU1.1): 62° C., softening starts at 55° C., Shore A hardness 54,65% by weight of an aqueous dispersion (particle diameter: 150 nm) of ahard polyurethane (PU2.2), obtainable by reaction of isophoronediisocyanate (a1.2), 1,4-butanediol, 1,1-dimethylolpropionic acid,hydrazine hydrate and polypropylene glycol having a molecular weightM_(w) of 4200 g/mol, softening point of 195° C., Shore A hardness 86,3.5% by weight of a 70% by weight solution (in propylene carbonate) ofcompound (V.1),

6% by weight of a 65% by weight aqueous dispersion of the siliconecompound according to Example 2 of EP-A 0 738 747 (f.1)2% by weight of carbon black,0.5% by weight of a thickening agent based on polyurethane,1% by weight of microballoons of polyvinylidene chloride, filled withisobutane,diameter of 20 μm, commercially obtainable for example as Expancel® fromAkzo Nobel.

This gave an aqueous dispersion Disp.1 having a solids content of 35%and a kinematic viscosity of 25 seconds at 23° C., determined inaccordance with DIN EN ISO 2431, as of May 1996.

I.2 Production of an Aqueous Formulation Disp.2

The following were mixed in a stirred vessel:

7% by weight of an aqueous dispersion (particle diameter: 125 nm, solidscontent: 40%) of a soft polyurethane (PU1.1) prepared from hexamethylenediisocyanate (a1.1) and isophorone diisocyanate (a1.2) in a weight ratioof 13:10 as diisocyanates and as diols, a polyester diol (b1.1) having amolecular weight M_(w) of 800 g/mol, prepared by polycondensation ofisophthalic acid, adipic acid and 1,4-dihydroxymethylcyclohexane (isomermixture) in a molar ratio of 1:1:2, 5% by weight of 1,4-butanediol(b1.2), 3% by weight of monomethylated polyethylene glycol (c.1) andalso 3% by weight of H₂N—CH₂CH₂—NH—CH₂CH₂—COOH, % by weight all based onpolyester diol (b1.1), softening point of 62° C., softening starts at55° C., Shore A hardness 54,65% by weight of an aqueous dispersion (particle diameter: 150 nm) of ahard polyurethane (α2.2), obtainable by reaction of isophoronediisocyanate (a1.2), 1,4-butanediol (PU 1.2), 1,1-dimethylolpropionicacid, hydrazine hydrate and polypropylene glycol having a molecularweight M_(w) of 4200 g/mol (b1.3), polyurethane (PU2.2) had a softeningpoint of 195° C., Shore A hardness 90,3.5% by weight of a 70% by weight solution (in propylene carbonate) ofcompound (V.1),NCO content 12%,2% by weight of carbon black.

This gave a polyurethane dispersion Disp.2 having a solids content of35% and a kinematic viscosity of 25 seconds at 23° C., determined inaccordance with DIN EN ISO 2431, as of May 1996.

I.3 Production of a Melamine Foam (A.1)

In an open vessel, a spray-dried melamine-formaldehyde precondensate(molar ratio 1:3, molecular weight about 500) was added to an aqueoussolution comprising 3% by weight of formic acid and 1.5% of the sodiumsalt of a mixture of alkyl sulfonates having 12 to 18 carbon atoms inthe alkyl radical (Emulgator K30 emulsifier from Bayer AG), thepercentages being based on the melamine-formaldehyde precondensate. Theconcentration of melamine-formaldehyde precondensate, based on theentire mixture of melamine-formaldehyde precondensate and water, was74%. The mixture thus obtainable was vigorously stirred, and then 20% ofn-pentane were added. Stirring was continued (for about 3 min) until adispersion having a homogeneous appearance had formed. This was bladecoated onto a Teflon-coated woven glass fabric support material andfoamed and cured in a drying cabinet in which the prevailing airtemperature was 150° C. The temperature resulting in the foam was theboiling point of n-pentane which is 37° C. under these conditions. After7 to 8 min, the foam had risen to its maximum height. The thusobtainable foam (A.1) was left in the drying cabinet for a further 10min at 150° C.; subsequently it was heat-conditioned at 180° C. for 30min and cut into sheets 3 cm in thickness.

Foam (A.1) was found to have the following properties:

DIN ISO 4590 open-cell factor: 99.6%,

DIN 53577 compressive strength (40%): 1.3 kPa,

EN ISO 845 density: 13.0 kg/m³,

average pore diameter 210 μm, determined by evaluation of micrographs ofsections,

DIN 66131 BET surface area: 6.4 m²/g,

DIN 52215 sound absorption: 93%,

DIN 52212 sound absorption: more than 0.9.

II. Production of a Mold

A liquid silicone was poured onto a surface having the pattern of fullgrain calf leather. The silicone was cured by adding a solution ofdi-n-butylbis(1-oxoneodecyloxy)-stannane as 25% by weight solution intetraethoxysilane as an acidic curative to obtain a silicone rubberlayer 2 mm in thickness on average, which served as the mold. The moldwas adhered onto a 1.5 mm thick aluminum support.

III. Application of Aqueous Polyurethane Dispersions onto Mold from II.

The mold from II. was placed on a heatable surface and heated to 91° C.Disp.1 was then sprayed onto it through a spray nozzle, at 88 g/m²(wet). No air was admixed during application, which was done with aspray nozzle having a diameter of 0.46 mm, at a pressure of 65 bar. Thiswas followed by solidification at 91° C. until the surface was no longertacky.

The spray nozzle was located 20 cm above the surface passing underneathit, and could be moved in the transport direction of the surface, andmoved transversely to the transport direction of the surface. Thesurface took about 14 seconds to pass the spray nozzle and had atemperature of 59° C. After being exposed for about two minutes to astream of dry hot air at 85° C., the polyurethane film (C.1) thusproduced, which had a netlike appearance, was almost water-free.

In an analogous arrangement, Disp.2 was immediately thereafter appliedto the mold thus coated, as bonding layer (B.1) at 50 g/m² wet, andsubsequently allowed to dry.

This gave a mold coated with polyurethane film (C.1) and bonding layer(B.1).

Foam (A.1) was sprayed with disp. 2, at 30 g/m² (wet). After a fewseconds, the surface of foam (A.1) appeared dry.

IV. Production of an Inventive Multilayered Composite Material

Thereafter, foam (A.1) was placed with the sprayed side onto the stillhot bonding layer (B.1) which was on the mold together with polyurethanefilm (C.1), and compressed in a press at 4 bar and 110° C. for 15seconds. The inventive multilayered composite material MSV.1 thusobtained was subsequently removed from the press and the mold wasremoved from it.

The inventive multilayered composite material MSV.1 thus obtained wasnotable for pleasant haptics, an appearance which was identical to aleather surface, and also breathability. In addition, the inventivemultilayered composite material MSV.1 was easy to clean of soiling suchas dust for example.

The invention claimed is:
 1. A multilayered composite material, comprising (A) a foam layer, wherein the foam is a polystyrene foam, a polyurethane foam, a polyester foam, a butadiene-styrene block copolymer foam, a natural sponge, an amino resin foam, or any mixture thereof; (B) a bonding layer comprising a cured organic adhesive; and (C) a polyurethane layer comprising hairs on a surface thereof and capillaries that pass through the entire thickness of the polyurethane layer (C), wherein the hairs on the surface of the polyurethane layer (C) have an average length in the range from 20-500 μm, and wherein the bonding layer (B) is interposed between the foam layer (A) and the polyurethane layer (C) such that the bonding layer (B) is in direct contact with the foam layer (A) and the polyurethane layer (C).
 2. The multilayered composite material of claim 1, wherein the foam layer comprises the amino resin foam and the amino resin foam comprises melamine-foam.
 3. The multilayered composite material of claim 1, wherein the bonding layer (B) comprises a continuous layer of a cured organic adhesive.
 4. The multilayered composite material of claim 1, wherein the bonding layer (B) comprises an interrupted layer of a cured organic adhesive.
 5. A piece of furniture, comprising the multilayered composite material according to claim
 1. 6. A vehicle, comprising the multilayered composite material of claim 1 in an interior.
 7. The multilayered composite material of claim 1, wherein the hairs on the surface of the polyurethane layer (C) have an average length in the range from 30-200 μm.
 8. The multilayered composite material of claim 1, wherein the hairs on the surface of the polyurethane layer (C) have an average length in the range from 60-100 μm.
 9. The multilayered composite material of claim 8, wherein an average spacing between adjacent hairs on the surface of the polyurethane layer is in the range from 100 to 250 μm.
 10. The multilayered composite material of claim 1, wherein an average spacing between adjacent hairs on the surface of the polyurethane layer is in the range from 50-350 μm.
 11. The multilayered composite material of claim 1, wherein an average spacing between adjacent hairs on the surface of the polyurethane layer is in the range from 100 to 250 μm.
 12. The multilayered composite material of claim 1, wherein the bonding layer (B) comprises spherical particles having an average diameter in the range from 5-20 μm.
 13. The multilayered composite material of claim 12, wherein the spherical particles comprise a polymeric material filled with n-butane, isobutene, or any mixture thereof.
 14. A process for producing the multilayered composite material of claim 1, the process comprising: forming a polyurethane layer (C) with the aid of a mold; applying an organic adhesive uniformly or partially onto foam (A) and/or onto polyurethane layer (C); and then, bonding the polyurethane layer (C) pointwise, stripwise, or areawise to foam (A).
 15. The process of claim 14, wherein the polyurethane layer (C) is formed with the aid of a silicone mold.
 16. The process of claim 14, wherein silicone mold comprises a silicone mold structured with the aid of laser engraving.
 17. The process of claim 14, wherein the mold is structured by cutting wells into the mold with a laser, wherein the wells have an average depth in the range from 50 to 250 μm and a center-to-center spacing in the range from 50 to 250 μm.
 18. A process for producing furniture, the process comprising forming the multilayered composite material of claim
 1. 